Kalk & low Mag?

[Jimnorris]

Joshua,
I supplement magnesium twice aweek. I add 60 ml of ESV magnesium. MY magnesium level before I started to add was 1300 which is consider with in the normal range but on the low side. I keep my level at 1400 to 1500. with is on the higher side. I am dripping kalk and use ESV B-ionics. I was enjoying good growth. It has been acouple months now that I have been adding magnesium and my SPSs growth is now GREAT! I have notice a big difference!
Jim

[Instar]

If a tank magnesium gets low, it is a good indicator of the overall health and capacity of the buffers in the sea water. If its low, the buffer is likely quite depleted, very out of balance and the chance for large pH swings are higher than normal. It may also mean the tank is on the verge of disasterous changes and low pH because the buffer capacity has been used up and it just won't handle any more waste processing. pH will not hold and reactions (calcium carbonate transfer) won't be right for skeletal building if the Mg++ is low and calcium hydroxide is high. Once you start dosing things that involving the buffer system, you have to keep all the major actors in balance.

[Tim Marvin]

I drip kalk and do water changes. That is it. I was going to dose but after testing, all my parameters seem to be on the high side. Calcium is in the 475-525 range every time I test. PH 8.2-8.4

[GaryP]

Magnesium also helps to stabilize soluble Calcium and Hardness, especially when you are running on the high side for both. Magnesium forms a soluble complex with carbonate and helps prevent precipitation of CaCO3. In other words, magnesium pushs the CaCO3 precipitation equilibrium towards the soluble species.
Magnesium Carbonate is much more soluble than calcium carbonate.

Gary

[GaryP]

This is what I tried to say in my previous post. I came across this and thought it did a better job than I did. I just thought I would throw it out there for anyone interested.

Through the chemical process known as "ion-pairing", magnesium ion concentration influences the saturation point for calcium carbonate in solution. In general, the further the magnesium concentration drops from natural seawater levels (1350 ppm), the more difficult it becomes to maintain adequate levels of both calcium and alkalinity. Magnesium also plays an important role in stabilizing pH by interacting with the buffer system of seawater.

[Tim Marvin]

I think it was 1550.

[Tim Marvin]

I don't know. All I do is water changes and dose kalk on the tank. It has a refugium with 3 inch of sand and the tank has about 3 inch deep sand...? Could it be leaching from the sand? I don't have a mag reactor so that couldn't be it....LOL.... Like I said also I think that was the numbers, I borrowed a test kit from Jim a few weeks back because I was considering useing the A B.

[Instar]

Normal sea water concentration for Mg is mis-reported often or varies between the analyst techniques. Its reported from 1140 to 1500. Thats quite a range there. Actual sea water concentration from what I can find on analysis reports is 1185 mg/L and coincidently is what I/O comes in at when mixed fresh with RO water.

[Tim Marvin]

Does 1550 sound right to you then Instar? I really don't do a lot of testing, as it tends to make me do things I wouldn't ordinarily do. I just watch the livestock and do water changes or dose more or less kalk when something doesn't look right to me. I guess I kinda know what my tank needs.

[Tim Marvin]

Nope, brand new test kit from Jim Norris. Salifert

[Instar]

Mg++ at 1550 mg/L is generally a little too high, but, your calcium level and pH is up in a good range. I wouldn't take the calcium above 525 though, as its harder to keep things in balance vs precipitating it out. And some mushrooms can start to bleach out at 525 from my experience. What kind of substrate are you using? Do you have a calcium reactor going? What do the membranes on your fish's eyes look like? They should be crystal clear with clear lenses on both omnivores and herbivores. What is your alkalinity with measurement units? I got your Ca++ and pH from the earlier post.

[Tim Marvin]

double posted.

[Tim Marvin]

2.8-3.2 milli equiv. Mushrooms reproduce like crazy as well as zoo's, LPS, SPS, and sponges. Fish eyes have always been crystal clear. 2 percula, midas blenny, half moon angel, hippo tang, and yellow tang.

[Instar]

Ok, your calcium is a bit high for that alkalinity. In this case the Magnesium will help stabilize the buffer.
WARNING: anyone reading this should not try to do it!
It would take nearly 1000 mls (1 liter) of Bionic Ca buffer part 1 to raise the dkh into the balance range with the calcium if the calcium averages 500 mg/L. Ths impact on the pH would be HUGE and your mushrooms and sponges will have a very negative reaction to that. It could even kill them. It would have to be done very slowly.
What I would do (this depends on your sand - there are some that are very rich in Mg and reducing the Mg in the system while raising the dkh a little may not be at all feasable if your substrate is highly concentrated magnesium.): Stop dosing calcium and anything with magnesium in it for a little while. That might be hard to raise the dkh then because many dkh raising compounds have a percentage of magnesium in them. Change water at 10% per change 2 times/month. Sponges seem to love a low dkh buffer capacity and you don't want to bring this into balance very quickly at all. As you add dkh buffer, if you so choose to add something, the calcium level will start to drop. As dkh goes up, calcium comes down. And conversely, as calcium goes up, dkh comes down. The balance, or optimum for both is a real trick because something is always getting used to generate skeletons, bones, spicules, algae, etc.
If those were the numbers in my 125, what I would do is to add 1/2 teaspoon of Seachem Reef Builder (dkh builder) disolved in a gallon of make up water, twice weekly. I would test the Mg, Ca, and dkh as I went. The sps corals will love the buffer and they will start to grow rather quickly you'll notice. If you add too much, too often, the sponges will react negatively. I would do this till I start to see the calcium come down a little and dkh up some. May even take a week or two off from adding the buffer and watch the calcium level for those two weeks. That is not a bad calcium to have, its just you need a little more buffer (dkh) in there for a higher read. The magnesium should come down naturally as you go. I would also pick up my water changes a little to maybe 10% change as much as 3 times a month. Probably for sure I would make it twice a month. As long as sponges are doing well and fish eyes are clear, there isn't a great need to change real fast, but, you do need to get the dkh up a bit for the sake of the LPS and SPS corals. Corals can assimulate magnesium into their skeletons b/c that ion has the same outer shell valance as calcium. Trouble is that its smaller, and some think that makes it easier to transport across the cell membrane and into the coral skeleton. My thoughts on this is that is may make the skeleton softer or more brittle and more likely to break poorly. With your calcium levels, pH, if the dkh buffer is increased a little and the magnesium decreased some, then you will have a pretty optimal coral skeleton building environment. I am not sure how the magnesium like that affects zoos. These things tend to adapt to what they have and start growing like crazy. Making any fast major change may stop the growth pattern for a while and can also release things that were preciptates back into solution. That can be good, or bad, depending on what you have built up in there over time. Slow change is the key. My real concern with yours is that the dkh is too low and you could see a pH fall off. The magnesium is preventing that to some degree, I am sure.

[Tim Marvin]

OK, tested this morning. PH 8.2 calcium 450, alk 2.8, mag 1350. Go figure. I'm useing Carrib Sea sand and pink Fiji.

[Instar]

Thats better, but, watch that pH close now, just in case. That alkalinity is still low if that test method is working and the reagents are good. The rest are great now. The sand you are using wouldn't boost the Mg too much, I don't think. Should help keep things just right actually. Some of our test kits for aquarium use are as much as 25 to 30% in error. In other words a true calcium of 525 may return a test value of 410 with an aquarium test kit. After all, when is the last time anyone ran a control on any kit other than a pH meter? Truthfully though, those numbers look like a balanced system with an alkalinity test kit that is a little off.

[Tim Marvin]

Hmm, the alk is up neear the top on the test kit, indicating it may be a tad on the high side.

[Instar]

Well, I must be on a different scale unit from your kit. What is the unit of measure on yours and the range of that kit?